A Russian trade union official has said that more than half a million scientists and computer programmers have left the country since the fall of the Soviet Union in 1991.

The chairman of the unions represented at the Russian Academy of Sciences, Viktor Kalinushkin, told a news conference in Moscow that most of them were finding well-paid jobs in the United States, Europe and Japan.

From 500,000 to 800,000 Russian scientists have left long-term missions abroad in the past 10 years - almost none of them have returned

Viktor Kalinushkintrade union chairman

The average monthly wage for Russian scientists is less than $100, while in the West they can earn $3-7,000 a month.

Mr Kalinushkin said physicists, biologists, chemists and computer programmers were in particularly high demand.

He said Russian-speaking programmers in the USA were responsible for developing 30% of Microsoft products.

Putin has made reviving Russian science a priority

State support for science in Russia has shrunk since the collapse of the USSR in 1991, but President Vladimir Putin has made it a priority to revive its prestige.

Mr Kalinushkin said there were currently two groups of scientists in Russia - young people under 30 who could be expected to leave to work abroad and an older generation around the age of 50, who usually remain behind.

"Between 500,000 and 800,000 Russian scientists have left on long-term mission abroad in the past 10 years," he said.

"Almost none of them have returned."

Japan, the USA, the UK, Canada, France and Germany were the main beneficiaries, he said.